The FR-4003 from Narda Safety Test Solutions is a RF Spectrum Analyzer with Frequency 9 kHz to 30 MHz, Frequency Resolution 1 Hz, Attenuation Range 35 to 40 dB, Spurious -10 dBuV(Response), AC Supply 100 to 240 VAC. Tags: Analyzer with Screen. More details for FR-4003 can be seen below.